The invention relates to lead-acid battery assembly, and more particularly to a method and apparatus for assembling plate separators about lead plates to be assembled into such batteries.
In a lead-acid battery, each cell contains a plurality of alternate positive and negative plates. These alternate plates must be insulated from one another and yet the liquid battery acid solution must be allowed access to the surfaces of each plate. To provide the required insulation, a sheet of liquid permeable separator material of paper or polypropylene, for example, is usually inserted between the surfaces of adjacent positive and negative plates. The separator material is generally quite porous and may include ridges along its surfaces to allow the battery acid free access to the plate surfaces. Thermoplastic porous materials such as melt blown polypropylene or polyethylene have been successfully made with a controlled porosity and thickness which readily adapts them for this use as a separator material.
Rather than using individual sheets of separator material between each pair of adjacent positive and negative plates, some battery assemblies employ a folded sheet of separator material or separator "envelope" about each of either positive or negative battery plates or both. This tends to simplify assembly while still providing the required insulation between all adjacent positive and negative plates. Folded or envelope-type separators have the additional advantage in that they protect the enclosed plate during assembly and also will retain any loose fragments of the active material (paste) which may become dislodged or loose during manufacture or subsequent use. The manner in which these folded separators or separator envelopes are applied to a group of battery plates varies with different assembly operations. Generally, however, there are some hand operations in the separator application process and in some cases the whole operation is accomplished by hand with the aid of light hand-operable machinery.